Sandbox: malabsorption

Diarrhea

Abbreviations: GI: Gastrointestinal; WBC: White blood cells; Plt: Platelets, Hgb: Hemoglobin, IgE: Immunoglobulin E, IgA: Immunoglobulin A

Categories		Cause	Clinical manifestation									Lab findings									Extra intestinal findings	Cause/Pathogenesis	Gold standard diagnosis
			Symptoms								GI signs
			Duration		Diarrhea			Fever	Abdominal pain	Weight loss
												Stool exam					CBC			Other lab findings
			Acute	Chronic	Watery	Bloody	Fatty					WBC	RBC	Ova/Parasite	Osmotic gap	Other	WBC	Hgb	Plt
Gastrointestinal		Crohns disease	-	+	+	+	+	+	+	+	Abdominal tenderness Tachycardia Hypotension				-		↑	↓	↑	Iron deficiency Vitamin B12 deficiency Elevated ESR Elevated CRP	Blood seen on rectal exam	Abnormal immune response to self antigens	Colonoscopy with biopsy
		Ulcerative colitis	-	+	+	+	+	+	+	+	Abdominal tenderness Tachycardia Hypotension Aphthous ulcers				-		↑	↓	↑	Hypoalbuminemia Hypokalemia Hypomagnesemia Iron deficiency Elevated ESR Elevated CRP	Skin rash Iritis Uveitis Seronegative arthritis Clubbing of the fingers Erythema nodosum	Abnormal immune response to self antigens	Colonoscopy with biopsy
		Celiac disease	-	+	±	-	±	-	+	+	Abdominal distention Mouth ulcers Hepatosplenomegaly Ascites				↑		-	↓	-	IgA endomysial antibody Anti-tissue transglutaminase antibody Anti-gliadin antibody	Signs of the fat-soluble vitamins A, D, E, and K deficiency Dementia Dermatitis herpetiformis	HLA-DQ2 HLA-DQ8 Innate responses to wheat proteins	IgA endomysial antibody IgA tissue transglutaminase antibody
		Cystic fibrosis	-	+	-	-	+	±	+	+					↑		-	↓	-	Positive DNA analysis for CFTR Evaluated nasal transepithelial potential difference (NPD)	Diabetes Recurrent upper and lower respiratory tract infections Infertility	Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) protein	Elevated sweat chloride ≥60 mmol/L
		Chronic pancreatitis	-	+	+	-	+	-	+	+	Abdominal tenderness				↑		-	-	-	Slightly elevated amylase and lipase Abnormal pancreatic function test	Malabsorption Diabetes mellitus	Repeated acute pancreatitis Alcohol abuse Genetic Autoimmune	Secretin stimulation test ERCP
		Microscopic colitis	-	+	+	+	-	-	+	+	Abdominal tenderness				-		-	↓	-	Elevated autoantibodies include: RF ANA AMA ANCA	Fecal urgency Fecal incontinence Arthralgia Arthritis Uveitis	Mucosal immune responses to luminal factors in a genetically predisposed individual	Colonoscopy with mucosal biopsy with mononuclear infiltrates: Collagenous colitis is characterized by a colonic subepithelial collagen band >10 micrometers in diameter Lymphocytic colitis is characterized by ≥20 intraepithelial lymphocytes (IEL) per 100 surface epithelial cells
		Infective colitis
		Ischemic colitis
		Mesenteric ischemia
		Lactose intolerance	+	+	+	-	-	-	+	-	Abdominal tenderness Hypotension Tachycardia Nausea and vomiting				↑		-	-	-	Hydrogen breath test	Bloating Flatulence Symptoms begin mainly after ingestion of lactose	Reduction of lactase enzyme activity or inability to produce persistent lactase Congenital lactase deficiency	Lactase activity assay
		Irritable bowel syndrome	-	+	±	-	±	-	±	-	Abdominal tenderness Flatulence Hard stool in the rectal vault				-		-	-	-				Diagnosis of exclusion
Infection	Bacterial	Whipple's disease	-	+	+	-	+	±	+	+	Hepatosplenomegaly Ascites	-	-	-	↑	Fecal fat	↓	↓	↓/↑	Hypoalbuminemia	Abnormal extraocular movement Lymphadenopathy Hyperpigmentation Uveitis Endocarditis Encephalitis Dementia Pleural effusion	Tropheryma whipplei HLA-B27	Small intestine biopsy for Tropheryma whipplei testing PCR testing
		Tropical sprue	+	+	+	-	+	+	+	+	Pallor Angular stomatitis Mouth ulcers Edema				↑		-	↓	-	Low vitamin B12 Low folic acid Hypokalemia		Unknown Bacteria including Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae	Diagnosis of exclusion
		Small bowel bacterial overgrowth	-	+	+	-	+	-	+	+	Muscle atrophy Abdominal distention						-	↓	-	Hypoalbuminemia Abnormal hydrogen breath test Lactic acidosis Abnormal fecal fat test	Malabsorption Vitamins deficiencies Rosacea	Excess bacteria in the small intestine Alterations in intestinal anatomy or GI motility,  Lack of gastric acid secretion	Diagnosis of exclusion
		Food poisoning
		Pseudomembranous colitis	+	-	+	+/-	-	+	+	+/-	Abdominal tenderness Presence of pseudomembranes of endoscopy					Enzyme immunoassay (EIA) for C difficile toxin A and B Polymerase chain reaction (PCR) assay or C difficile antigen (glutamate dehydrogenase [GDH]) EIA	↑	↓	↓	Leukocytosis Elevated serum creatinine Hypoalbuminemia Anasarca Elevated serum lactate		Recent antibiotics use Recent surgery Colon cancer Diverticulitis Appendicitis	Stool exam CT
		Shigellosis
		Salmonella
		Campylobacter jejuni
		E-coli
		Yersinia enterocolitica
		Vibrio cholera
		Aeromonas
		Plesiomonas
		Mycobacterium avium complex		+		+		+/-	+	-		+/-	+	-	-		↓	-	-	Immune system analysis may show defects
		Other infections aaaa bbbb		+		+		-	+	+/-		+	+	-	-	Stool culture may be positive for responsible organism	↑	-	-
	Virus	Rotavirus
		Echovirus
		Adenovirus
		Norovirus
		CMV colitis		+		+		+/-	+	-		+/-	+	-	-		↓	-	-	CD 4 level decreased as it is maily associated with HIV
		HIV
		Hepatitis A
		Hepatitis E
	Parasite	Entamoeba histolytica
		Giardiasis
		Cryptosporidiosis
		Microsporidiosis
		Isosporiasis		+		+			+	-		+	+	-	-		↑	-
		Other Parasitic diarrhea aaaa bbbb	+	+		+		-	+	+/-		+	+	+	-		↑	-	-
Tumors		Carcinoid tumor
		VIPoma	+	+	+	-	+	-	+	+	Tachycardia Abdominal distention Abdominal RUQ tenderness Nausea Vomiting				↓		-	-	-	Elevated VIP level Hypokalemia Hypochlorhydria or achlorhydria Low osmotic gap (<50 mOsm/kg)	Rash Facial flushing Dehydration Lethargy Muscle weakness	Primary secretory tumor	Elevated VIP levels Followed by imaging
		Zollinger-Ellison syndrome	-	+	+	-	+	-	+	+	Abdominal tenderness				↓		-	↓	-	Positive secretin stimulation test Elevated serum chromogranin A	Heartburn	Gastrin producing tumor mainly in duodenum	Elevated basal or stimulated serum gastrin> 120 pg/mL
		Somatostatinoma
		Colorectal cancer		+		+			+	+		-	+	-	-		-	↑/↓	-	May be associated with FAP gene or HNPCC gene
Medication/Toxicity		Drug induced enteritis
		Chronic laxative abuse
		Heavy metal ingestion
		Organophosphate poisoning
Iatrogenic		Short bowel syndrome	+	+	+	-	+	-	-	+	Abdominal distention Abdominal tenderness Peripheral edema Muscle atrophy				↑		-	↓	↑	Hypoalbuminemia High level of acute phase reactant Abnormal liver function tests Low vitamin A, B12, C,D, E, and K level High fecal fat	Prior intestinal surgery Crohn's disease Malignancy Radiation enteritis	Surgical intestinal resection
		Radiation enteritis
		Dumping syndrome
Metabolic		Abetalipoproteinemia	-	+	+	-	+	-	+	+	Abdominal distension Visual field defect Dysarthria						-	-	-	Low triglyceride Low total cholesterol levels  Acanthocytes Low vitamin E levels	Visual impairment Ataxia	Autosomal recessive disorder caused by mutations encoding the microsomal triglyceride transfer protein (MTP)	Clinical findings and low triglyceride and cholesterol level
		Hyperthyroidism	-	+	+	-	-	±	+	+	Lump in the neck Proptosis Tremor Increased DTR						-	-	-	Elevated T4 Elevated T3 Decreased TSH	Lid lag Sweating Hyperpigmentation	Graves' disease Hashimoto's thyroiditis Toxic adenoma	TSH